The discovery of a mechanical exfoliation method for two-dimensional (2D) crystals was a watershed moment in the search for materials for the next generation of electronics and energy production. Among layered crystals amenable to isolation of atomically thin monolayers is a family of TMDs having the chemical formula MX2, where M is a transition metal, and X is S, Se, or Te. A semiconducting subset of TMDs includes those in which the transition metal M is Mo or W (both in Group 6), and has received attention in the pursuit of applications including ultrathin flexible electronics and spintronics. In an energy context, these materials hold promise as hydrogen evolution catalysts when certain features are exposed to a reacting environment.
It is against this background that a need arose to develop the techniques for inducing phase transformation in TMDs and related devices and methods described herein.